Hot-air furnace



April 17, 1926. 1,666,736

. F. A. CONRAD HO'I AIR FURNACE Filed May 29, 1924 4 Sheets-Sheet 1 INVENTOR. fkq NK A. CONRAD W wh /MM ATTORNEYS.

April 17, 1928. v v 1,666,736

- F. A. CONRAD HOT AIR FURNACE Filed May 29, 1924 4 Sheets-Sheet 2 I N vE/vToR! FRANK A. CONRAD.

' Win4 Mm ATTORNEYS.

F. A. CONRAD HOT AIR FURNACE Filed May 29, 1924 4 Sheets-Sheet 3 1 ATTORNEYS.

April 17, 1928.

F. A. CONRAD now AIR FURNACE Filed May 29, 1924 4 Sheets-Sheet 4 INVENTOR: ffivvwr A. CONRAD.

ATTORNEYS.

Patented Apr. 17, 1928.

f FRANK A. oommn, -01

AT TO F s'r. PAUL, MINNESOTA.

Application filed May 29,

My invention relates to hot air furnaces, and an object is to provide a furnace of this type inw'hich the heat'going to the various rooms is equally distributed, so that all of the rooms in the building will receive their proper share of heat regardless of conditions tending to cause a greater flow of heated air to some of the rooms than to other rooms. Another objectis to moisten and .clean the heated air suppliedto-the rooms. Another object isto conserve heat and preventwaste o'fffuel. A Y he The full object-s andadvantages of my in-' vention will appear-in connection with the detailed description, and the novel features embodied in my inventive idea will be par-' ticularly pointed :out in the claims. I s

In the accompanying ,drawings which, illustrate the application of .my invention in slightly different forms, Fig. 1 is a vie-wof my furnace in vertical section. Fig. .2 is a View in horizontal {section on the 1ine'2.-'2 .of Fig. 1. F ig. t3 is a view iirhorizontal section on the line 3-3- of Fig. 1. Fig.4 is a view in vertical section onthe line 4-4 of Fig. 2. Fig. 5 is .a view in horizontal section on the line 5 -5 of Fig. 1. Fig.6 is a View of 1 a slight modification in horizontal section above the feed door. Fig. .7 is a View corresponding ,to. Fig. 4 .and showing a modified. formf "Fig. 8 is aview in horizontalksect-ion. of the form shown in Fig. 7. Fig. 9 is aview corresponding :to Fig. and showing a further modification.

Referring to the construction shown in the drawings and first, more particularly Figs. 1 to 5, the numeral .10. designates the firebox of a :hot-air'furnace having .a casing .12 toward the, lower endof .which-. the fire- :box 10 and :grate 14' are located, the ashpit 1.6 and fits door 18 .being below the grate. .The casing 12v is provided as usual with a feed-door 20 and a smokeflue 22. Surrounding and spaced from the casing 12 is a polygonal casing 24having partitions 26 extending from its apices to the casing 12, wherebya plurality. of chambers 28 are formed, these chambers being closed at their tops and open at :their bottoms, as shown in Figs. land 4. Surrounding and spaced from thecasing24 which may .betermed an intermediate casing, is an outer casing or shell 30 providedv .at its upperend witha fresh-air inlet pipe 32. Shortfpipe sections "34 extend outwardly from openings ,at the upper ends of the hot-:air chambers 28. The

1924. Serial No. 716,820. I

pipe sections 34 extend'fo'rv a short distance through openings 36 in the casing 80 as bestv shown in Fig. 4, the pipe sections being smaller than the openings, so that an exit fromthe space within the casing 24 is provided into the hot-air pipes 38. The pipe sections 34 also deliver air into the 'hot-air' pipes 88., the capacity of the pipe sections 84 being preferably about double that of the annularportion s of theopenings 36 which surround the pipe sections 34. The inter mediate casing 24 stops short of the bottom of the furnace, and below the lower end of this casing is a water receptacle 40 which ex tends around annularly at the bottom of the furnace, except that it is interrupted at the place occupied by the ashpit door 18. The

form of the invention shown inFig. 6 is similar to that already described, the difference .beingthat the partitions 26 within the casing 24 are omitted, and,'as shown, this casing is circular in cross-section instead of being polygonal. 'Inthe form of my invention'illust-rated in Figs. 7 and 8, the casings .12., 24, and 30. are rectangular in shape.

Vertical partitions 26 extend between :the

1,666,736 1 ICE.

casings 12 and24. The hot-air pipes 38 iextend. from the top of the outer casing. Fresh air entering t-hrough the inlet pipe 32 passes around 'the pipe sections 34 and downwardly between the casings 30 and 24 passing out through the pipe sections 34.

and then upwardly between the casings 12 and. 24, thereby becoming heated, and then The form shown inFig. 9 differs from that shownin Figs. 7 :and 8 on account of having the fresh air pipe 32. connected tothe side i of the casing or shell 30 instead of to the top.

The operation and advantages of my invention will be understood in connection with the foregoing description. Fresh air entering througlrthe inlet pipe 32 passes downwardly into the furnace between the outer casing 30 and the casing 24, and after :coming into contact with the water in the receptacle 40 passes upwardlybetween the.

casing-24 and the inner casing 12. The air when it passesovcr the water,'-takes up mois- ,ture and 1s freedfrom impurities. From vthe space between the' inner casing 12 and the casing 24, the heated and moistened air passes through theshort pipe sections'34 into the hot air pipes 38 which supply hot air to the different rooms of the building. Under ordinary working conditions of the furnace, the pipes 38 will receive all or the greater portion of their supply of air through the pipe sections 34. However, if conditions arise so that one or more of the pipes 38 start to convey more than their proper amount of heated air, whereby the suction through such pipes is materially increased, then some of the fresh air coming in through the inlet pipe 32 will pass through the annular openings 36 around the pipe sections 84;, thereby reducing the amount of heated air passing through the sections 34. The arrangement described, therefore, acts as an equalizer to keep the rooms heated by the furnace at a uniform temperature regardless of extraneous conditions, such as the direction of the Wind. As will be apparent from Fig. 2, it will be understood that in one form of the invention, it is contemplated that there will be one of the chambers 28 and its associated pipe section 34c leading into a hot air supply pipe 38 for each room of the building which is to be heated by the furnace. The provision of the outer casing spaced outside of the casing 24 causes a saving of fuel. This results from the fact that the fresh air passes down through the space between these two cas- I ings so that the outer casing is kept cool and very little heat is radiated into the basement or other place where the furnace is located.

The employmentof my invention eliminates obstruction in the basement or cellar on account of the cold air intake being placed at the ceiling instead of at the floor, thereby saving space and conserving light, and the fresh air intake may also be somewhat smaller than usual. Inside or outside air is just as easily delivered to the plant, there being no difference in the construction or appearance ofthe intake pipe except that when inside air is taken an inside intake register must be attached tothe pipe near the floor. My furnace has a cool outer shell at all times and under all conditions of operation. This is the case because the outer shell is in effect a continuation of the cold air intake itself. A cool outer shell tends to a saving of fuel and heat, besides keeping the basement cool. The admitted fresh air is divided before and not after it is heated or has come in contact with the heater core. This method assures the accurate distribution of the air after it is heated. There are no overheated conduit pipes. On account of the accurate division of the incoming air with respect to the heat generated within the apparatus all of the hot air supply pipes are at the same temperature which under normal conditions of firing would mean moderately warm. The conduit pipes need not be run-at any particular pitch and neither need there be much concern that one pipe may be longer or of a longer run than some of the others. The conduit pipes may run on a level or may even form an inverted U provided that a reasonable elevation of the final. outlet is maintained above the plant itself. This is possible because of the heat engine character of the apparatus in that air is forced by the action of heat upon it to flow through and out of the apparatus by way of the channels provided therefor. As

a consequence a more convenient placing of theapparatus in the basement is provided.

Another feature is the standard size of'sthe conduit pipes which carry heated air from the apparatus. These pipes do not need to be more than eight inches in diameterwhich in itself involves a saving of light and space tributed to the remaining hot air pipes. I

The partitions 26 and 26' provide means for dividing the air before it is heated for dis tribution so that the cold, air is? forced against every square inch of the heated metal.

I claim: 1. In a hot air furnace, the combination of a plurality of hot air pipes leading there from, means for supplying cold air to the furnace to be heated thereby, and a plurality of short pipe sections smaller than said hot air pipes and corresponding in number thereto for conducting hot air supplied by the furnace into said pipes respectively, said pipe sections being so arranged that some of the cold air entering the furnace may pass outside of said sections directly into said pipes to equally distribute the amount of hot air delivered by all of said pipes for varying directions of the wind. I

2. In a hot air furnace, the combination of a plurality of hot air pipes, an intermediate casing surrounding and spaced from the furnace casing, the lower end' of said intermedi ate casing stopping short of the bottom of the furnace, an outer casing from which said hot air pipes lead, said outer casing surrounding and being spaced from said intermediate casing with its lower end extending to the bottom of the furnace, a freshair pipe leading into the space between said intermediate and outer casings, and a plurality of short pipe sect-ions smaller than said hot air pipes and corresponding in number thereto for conducting hot air from the space between said intermediate and the furnace casing into said pipes respectively, said pipe sections being so arranged that some of the cold air supplied by said fresh air pipe may pass outside of said sections directly intosaid pipes to equally distribute the amount of hot.

v rality of hot air pipes leading from the ing directions of the wind.

3. In a hot air furnace, the combination of an intermediate casing surrounding and spaced from the furnace caslng, the lower end of said intermediate casing stopping short of the bottom of the furnace, an outer casingsurrounding and spaced from said intermediate casing with its lower end ex:

tending to the bottom of the furnace, a pluupper vportion of said outer casing, a fresh air pipe leading into the upper portion of the space between said intermediate and outer casings, and a plurality of short pipe sect ions extending from said intermediate casing into the inner ends of said hot air pi s respectively, said pipe sections being smal er than said hot air pipes whereby annular openings are provided through which some of the cold air supplied by said fresh air pipe may be delivered directly into said hot air pipes to equally distribute the amount of hotair delivered by all of said pipes for varying directions of the wind.

In testimony whereof I hereunto aflixmy signature. 7 I FRANK A. CONRAD. 

